ghwikipp: pandoc-filter: only drop md/mediawiki file extensions if not an external URL.

SDL Commits
1 
From 470ba01dbeb10e9faf339d72b17175408df3e0ee Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <[EMAIL REDACTED]>
Date: Sun, 25 May 2025 10:01:12 -0400
Subject: [PATCH] pandoc-filter: only drop md/mediawiki file extensions if not
 an external URL.

Fixes https://github.com/libsdl-org/sdlwiki/pull/798
---
 pandoc-filter.lua | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/pandoc-filter.lua b/pandoc-filter.lua
index 97c8a8f..2e34b57 100644
--- a/pandoc-filter.lua
+++ b/pandoc-filter.lua
@@ -7,8 +7,10 @@ function Link (link)
   end
 
   -- drop any Markdown or MediaWiki file extensions that might have snuck in.
-  link.target = string.gsub(link.target, '%.md$', '')
-  link.target = string.gsub(link.target, '%.mediawiki$', '')
+  if not external_url then
+    link.target = string.gsub(link.target, '%.md$', '')
+    link.target = string.gsub(link.target, '%.mediawiki$', '')
+  end
 
   -- !!! FIXME: this doesn't work with subdirs, figure out why this was like this at all.
   -- If it's not an absolute path, not an external URL, and not a section link, make it absolute.